Cloth push-back and pass-through

[danazoid]

Nope. Both the PBD paper and Obi's code divide by the total inverse mass. A / (1 / B) = A * B.
Still, constraint * (massA + massB) is not correct since 1/A + 1/B != 1/(A+B), should have said constraint / (1/massA + 1/mass B). My bad!

Oh I made a typo by putting the * instead of /.
Thanks for the confirmation!

Unity solves for impulses, same thing Obi does. You accumulate multiple impulses on a rigidbody (some come from Obi, some come from Unity joints), and end up with the final velocity.

Ok I think I can explain what I observe wrt mass.
The user experiences the displacement of the tool from the VR hand.
The displacement is proportional to the force/impulse on the tool from the cloth.
Based on the PBD equations, increasing either massA or massB (either cloth OR tool), increases the impulse on the tool, so gives a larger displacement.
Does that sound right?

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The other issue is the tool collider shape.
Changing the mass of the cloth / tool doesn't help all that much.
The forceps and the long thin cylinder tend to pass through the cloth without much force.
Any suggestions on preventing this? The forceps can't really change its dimensions.